Three-dimensionally stacked memory has been proposed to increase the storage capacity of nonvolatile semiconductor memory devices. In a three-dimensionally stacked memory, for example, a stacked body including alternately stacked insulating films and electrode films, a silicon pillar that pierces the stacked body in the stacking direction, and a memory film interposed between the silicon pillar and the electrode films are provided. Thereby, a memory cell is provided at the intersection between the silicon pillar and each of the electrode films. Further, a configuration is conceivable in which a memory string has a U-shaped configuration in which two silicon pillars are connected on the substrate side.
Such a three-dimensionally stacked memory is expected to further reduce the size of the memory cells and further increase the storage density.